Comment on: “Spatial characterization of skin lesions in discoid and systemic lupus erythematosus”. Zhou W, Huang Y, Lei Y et al. Nature Communications 2026.
PMID: 42115607
Commented by: Assoc. Professor Anne Troldborg, Department of Rheumatology, Aarhus University Hospital and Biomedicin, Aarhus University, Denmark.
In this elegant study, Zhou and colleagues apply single-cell spatial transcriptomics (Stereo-seq) to skin lesions from patients with discoid lupus and systemic Lupus erythematosus (SLE), generating a high-resolution map of the cellular interactions that shape cutaneous disease. The authors identify two spatially distinct inflammatory niches: an interferon-rich compartment characterised by CXCL10-expressing “stress keratinocytes” at the dermal–epidermal junction, and tertiary lymphoid structure (TLS)-like aggregates enriched for B cells, T cells and specialised endothelial cells within more chronic lesions.
Several aspects of these findings are consistent with existing knowledge. Over the past decade, studies have established that keratinocytes are not merely passive targets of inflammation but active participants in lupus pathogenesis. Work from Kahlenberg and colleagues, among others, has highlighted the capacity of keratinocytes to amplify interferon-driven immune responses and shape local inflammatory networks. Similarly, increasing evidence suggests that tissue-resident interferon activity may be a critical determinant of disease expression, extending beyond what can be captured by peripheral blood biomarkers alone.
The major advance of the present study is therefore not the identification of interferon pathways per se, but the ability to place these pathways within their precise tissue context. By combining spatial transcriptomics with single-cell analyses, the authors demonstrate where potentially pathogenic cell populations are located, how they are organised within lesions, and which cellular interactions may sustain inflammation over time. This spatial perspective provides a new framework for understanding why different forms of cutaneous lupus may exhibit distinct clinical behaviours and treatment responses.
Particularly intriguing is the proposed distinction between acute inflammatory activity associated with stress keratinocytes and chronic disease associated with organised TLS-like structures. The identification of highly organised TLS-like aggregates containing age-associated B cells (ABCs), precursor germinal centre B cells, Tph/Tfh cells and regulatory T cells is especially noteworthy. ABCs have emerged as a key B-cell population in SLE and are increasingly linked to extrafollicular autoimmune responses, yet their spatial organisation within lupus target tissue has remained poorly understood. While these observations require confirmation in larger cohorts and remain largely associative, they suggest that different pathogenic programmes may dominate at different stages of disease evolution.
Overall, this study represents an important methodological and conceptual advance for the field. Rather than identifying entirely new pathways, it provides a more sophisticated view of how established lupus mechanisms are organised within diseased tissue. The findings suggest that acute inflammatory lesions may be dominated by interferon-responsive stress keratinocytes, whereas chronic lesions may be sustained by local immune niches enriched for ABCs, Tph/Tfh cells and other TLS-associated populations. Such spatially resolved approaches are likely to play an increasingly important role in refining disease classification, biomarker development and, ultimately, tissue-directed therapeutic strategies in lupus.